The most common and most likely answer to this crossword clue is the 4 letter word LOBO
I've seen this crossword clue in Financial Times
L
O
B
O
More clues leading to the result LOBO
Buddy explains!
The straight part
We know that "US wolf" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case us wolf = lobo.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does LOBO mean?
LOBO noun- A wolf.